/*
 * Copyright (c) 2017 Universidad de la República - Uruguay
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Matías Richart <mrichart@fing.edu.uy>
 */

#ifndef RRPAA_WIFI_MANAGER_H
#define RRPAA_WIFI_MANAGER_H

#include "ns3/nstime.h"
#include "ns3/random-variable-stream.h"
#include "ns3/wifi-remote-station-manager.h"

namespace ns3
{

struct RrpaaWifiRemoteStation;

/**
 * \ingroup wifi
 * Robust Rate and Power Adaptation Algorithm
 *
 * This class implements the RRPAA algorithm as described in <i>Rate, Power and Carrier-Sense
 * Threshold Coordinated Management for High-Density IEEE 802.11 Networks</i>
 * by Matías Richart; Jorge Visca and Javier Baliosian in Integrated Network Management (IM),
 * 2015 IFIP/IEEE International Symposium on (pp. 139-146). IEEE.
 * https://ieeexplore.ieee.org/document/7140286
 *
 * RRPAA adds power control to the RRAA mechanism. RRAA is described in
 * <i>Robust rate adaptation for 802.11 wireless networks</i> by Starsky H. Y. Wong;
 * Hao Yang; Songwu Lu and Vaduvur Bharghavan in Proceedings of the 12th annual
 * international conference on Mobile computing and networking (pp. 146-157). ACM.
 * http://ocw.cs.pub.ro/courses/_media/isrm/articole/rrate_adapt_mobicom06.pdf
 *
 * This RAA does not support HT modes and will error
 * exit if the user tries to configure this RAA with a Wi-Fi MAC
 * that supports 802.11n or higher.
 */

/**
 * For each rate there is a Opportunistic Rate Increase threshold,
 * a Maximum Tolerable Loss threshold and an Evaluation Window.
 */
struct WifiRrpaaThresholds
{
    double m_ori;    //!< The Opportunistic Rate Increase threshold.
    double m_mtl;    //!< The Maximum Tolerable Loss threshold.
    uint32_t m_ewnd; //!< The Estimation Window size.
};

/**
 * List of thresholds for each mode.
 */
typedef std::vector<std::pair<WifiRrpaaThresholds, WifiMode>> RrpaaThresholdsTable;

/**
 * List of probabilities.
 */
typedef std::vector<std::vector<double>> RrpaaProbabilitiesTable;

class RrpaaWifiManager : public WifiRemoteStationManager
{
  public:
    /**
     * Register this type.
     * \return The object TypeId.
     */
    static TypeId GetTypeId();
    RrpaaWifiManager();
    ~RrpaaWifiManager() override;

    void SetupPhy(const Ptr<WifiPhy> phy) override;
    void SetupMac(const Ptr<WifiMac> mac) override;

    /**
     * Assign a fixed random variable stream number to the random variables
     * used by this model.  Return the number of streams (possibly zero) that
     * have been assigned.
     *
     * \param stream first stream index to use
     *
     * \return the number of stream indices assigned by this model
     */
    int64_t AssignStreams(int64_t stream) override;

  private:
    void DoInitialize() override;
    WifiRemoteStation* DoCreateStation() const override;
    void DoReportRxOk(WifiRemoteStation* station, double rxSnr, WifiMode txMode) override;
    void DoReportRtsFailed(WifiRemoteStation* station) override;
    void DoReportDataFailed(WifiRemoteStation* station) override;
    void DoReportRtsOk(WifiRemoteStation* station,
                       double ctsSnr,
                       WifiMode ctsMode,
                       double rtsSnr) override;
    void DoReportDataOk(WifiRemoteStation* station,
                        double ackSnr,
                        WifiMode ackMode,
                        double dataSnr,
                        uint16_t dataChannelWidth,
                        uint8_t dataNss) override;
    void DoReportFinalRtsFailed(WifiRemoteStation* station) override;
    void DoReportFinalDataFailed(WifiRemoteStation* station) override;
    WifiTxVector DoGetDataTxVector(WifiRemoteStation* station, uint16_t allowedWidth) override;
    WifiTxVector DoGetRtsTxVector(WifiRemoteStation* station) override;
    bool DoNeedRts(WifiRemoteStation* st, uint32_t size, bool normally) override;

    /**
     * Check for initializations.
     * \param station the remote station.
     */
    void CheckInit(RrpaaWifiRemoteStation* station);

    /**
     * Check if the counter should be reset.
     *
     * \param station the remote station
     */
    void CheckTimeout(RrpaaWifiRemoteStation* station);
    /**
     * Find an appropriate rate and power for the given station, using
     * a basic algorithm.
     *
     * \param station the remote station
     */
    void RunBasicAlgorithm(RrpaaWifiRemoteStation* station);
    /**
     * Run an enhanced algorithm which activates the use of RTS
     * for the given station if the conditions are met.
     *
     * \param station the remote station
     */
    void RunAdaptiveRtsAlgorithm(RrpaaWifiRemoteStation* station);
    /**
     * Reset the counters of the given station.
     *
     * \param station the remote station
     */
    void ResetCountersBasic(RrpaaWifiRemoteStation* station);

    /**
     * Initialize the thresholds internal list for the given station.
     *
     * \param station the remote station
     */
    void InitThresholds(RrpaaWifiRemoteStation* station);

    /**
     * Get the thresholds for the given station and mode.
     *
     * \param station the remote station
     * \param mode the WifiMode
     *
     * \return the RRPAA thresholds
     */
    WifiRrpaaThresholds GetThresholds(RrpaaWifiRemoteStation* station, WifiMode mode) const;

    /**
     * Get the thresholds for the given station and mode index.
     *
     * \param station the remote station
     * \param index the mode index in the supported rates
     *
     * \return the RRPAA thresholds
     */
    WifiRrpaaThresholds GetThresholds(RrpaaWifiRemoteStation* station, uint8_t index) const;

    /**
     * Get the estimated TxTime of a packet with a given mode.
     *
     * \param mode the WifiMode
     *
     * \return the estimated TX time
     */
    Time GetCalcTxTime(WifiMode mode) const;
    /**
     * Add transmission time for the given mode to an internal list.
     *
     * \param mode the WifiMode
     * \param t transmission time
     */
    void AddCalcTxTime(WifiMode mode, Time t);

    /**
     * typedef for a vector of a pair of Time, WifiMode.
     * Essentially a list for WifiMode and its corresponding transmission time
     * to transmit a reference packet.
     */
    typedef std::vector<std::pair<Time, WifiMode>> TxTime;

    TxTime m_calcTxTime; //!< To hold all the calculated TxTime for all modes.
    Time m_sifs;         //!< Value of SIFS configured in the device.
    Time m_difs;         //!< Value of DIFS configured in the device.

    uint32_t m_frameLength; //!< Data frame length used to calculate mode TxTime (in bytes).
    uint32_t m_ackLength;   //!< Ack frame length used to calculate mode TxTime (in bytes).

    bool m_basic;   //!< If using the basic algorithm (without RTS/CTS).
    Time m_timeout; //!< Timeout for the RRAA BASIC loss estimation block.
    double m_alpha; //!< Alpha value for RRPAA (value for calculating MTL threshold)
    double m_beta;  //!< Beta value for RRPAA (value for calculating ORI threshold).
    double m_tau;   //!< Tau value for RRPAA (value for calculating EWND size).
    double m_gamma; //!< Gamma value for RRPAA (value for pdTable decrements).
    double m_delta; //!< Delta value for RRPAA (value for pdTable increments).

    /**
     * Differently form rate, power levels do not depend on the remote station.
     * The levels depend only on the physical layer of the device.
     */
    uint8_t m_minPowerLevel; //!< Minimal power level.
    uint8_t m_maxPowerLevel; //!< Maximal power level.
    uint8_t m_nPowerLevels;  //!< Number of power levels.

    /**
     * The trace source fired when the transmission power change
     */
    TracedCallback<double, double, Mac48Address> m_powerChange;
    /**
     * The trace source fired when the transmission rate change
     */
    TracedCallback<DataRate, DataRate, Mac48Address> m_rateChange;

    Ptr<UniformRandomVariable>
        m_uniformRandomVariable; //!< Provides uniform random variables for probabilistic changes.
};

} // namespace ns3

#endif /* RRPAA__WIFI_MANAGER_H */
